1. Field of the Invention
The present invention relates to a wafer processing apparatus and a wafer processing method using the same, and more particularly, to a wafer processing apparatus which can be used to form metal wiring layers having a multi-layered structure and a wafer processing method using the same.
2. Description of the Related Art
As the integration density of semiconductor devices increases, it is necessary to introduce metal wiring layers having a multi-layered structure into circuits. Because metal wiring layers transmit electrical signals, it is advantageous to use an economical material for the metal wiring layers which has low electrical resistance and high reliability. To meet these demands, aluminum is widely used for the material of the metal wiring layers. It is also advantageous to electrically connect such aluminum wiring layers in a way that is reliable, economical, and has low electrical resistance. Metal wiring layers are typically connected by a contact hole, which is a contact between a lower device and an upper wiring layer, or a via hole, which is a contact between a lower metal wiring layer and an upper aluminum wiring layer. Aluminum is preferably used as the metal to fill a contact hole or a via hole because it is economical and has superior conductivity.
To obtain superior electrical characteristics and filling characteristics when filling a contact hole or a via hole with aluminum, a variety of processing techniques have been developed. The processes for filling a contact hole or a via hole typically include steps such as chemical vapor deposition (CVD), physical vapor deposition (PVD), heat treatment, an oxidation process, and an etching process. Various cluster tool type wafer processing apparatuses have been developed to perform the steps for filling a contact hole or via hole.
However, a conventional integrated cluster tool type wafer processing apparatus typically does not have every facility required for performing all the processes for filling a contact hole or a via hole on a wafer. Accordingly, a vacuum break inevitably occurs during the contact hole or via hole filling processes. If a wafer is exposed to the atmosphere during the processes for filling a contact hole or a via hole, the exposed surface of the wafer may be contaminated by air, water vapor, or particles in the air, which may adversely affect the performance and yield of the resulting semiconductor device. In addition, the distance the wafer moves is increased significantly because the wafer is moved into a processing equipment or processing atmosphere which is not installed in the wafer processing apparatus during the contact hole or via hole filling process and through put is decreased.